Dynamically adding rows to a sub-form. Problem with populating drop-down list

Hello,

I need help on the following code. Here I am inserting rows in a sub-form called Period_Info1 (which is in main form Create_Time_Table) from another sub-form AA.Period_info.

The fields Period_no, Fr_Time and To_Time are inserted correctly but field Course, which is a drop-down list is not getting populated with List L_S. If the number of rows in the sub-from are predefined then the drop-down gets populated correctly from the list L_S.

The drop-down is not populated when it is part of the first loop (rowN.Course:ui.add(L_S)) or even later as I try to do it thru second loop below (rec9.Course:ui.add(L_S)). By both methods the drop-down list is not populated. It does not give any syntax error. This is happening with the drop-down list only.

I am stuck and I need help urgently. Thanks in advance for helping me.